NRAS and melanoma: It is possible that using an additional p-S6 inhibitor would result in a further synergistic effect, as observed in NRAS-driven melanoma xenograft models (Posch et al., 2013); however, combination p-AKT-p-S6 inhibitors, such as BEZ235, have also been shown to limit synergistic growth inhibition when combined with MEK inhibition (Haagensen et al., 2012).